X10 - oh no!

I just hooked up a PC interface last night, and was very distraught with the results. I can see X10 messages going by, but when I set up a map file to, say, play the stereo on X10:on[a1], it never does. The command shows up in the view window but it's never acted on. Of course, I did save the map file, reload, etc, and I can *send* x10 commands via a map file. It looks like you can't trigger events based on X10 input! Colby, say it ain't so!